It has been known for some time that boronates form reversible 5 membered ring complexes with saccharides. More recently, this property of boronates has been utilized in the development of sensors for the measurement of glucose in biological fluids. For example, a sensor may comprise a glucose receptor (the boronic acid) and a fluorophore that acts as the transmitter of the signal. These indicator chemistries can readily be immobilised onto an optical fibre of appropriate diameter, which can then be placed into body fluids or tissue to measure glucose.
It has been known for some time that boronic acids reversibly complex with glycosylated and glycated proteins. Although attempts have been made to devise sensing boronic acid chemistries that are selective it is obvious that glycated proteins represent potential interferents in the determination of glucose in body fluids when boronic acids are used as the sensor. Also other middle to high molecular weight endogenous materials have the potential to interfere with the boronic acid receptor by acting as quenchers of the transmitting fluorophore.
Further, although little has been known about the normal levels of reactive oxygen species (ROS) such as hydrogen peroxide (H2O2) in the blood, it is thought that residual levels of ROS normally present in the blood are very low, and thus the potential of ROS as a possible interferent in the determination of glucose in body fluids when boronic acids are used as the sensor has not previously been considered.